Pallets have been in wide use for many years to minimize the cost of handling products or articles that can be stacked or otherwise secured on them to thus enable large volumes of products or articles to be handled simultaneously and to be handled in mechanized fashion so as to minimize labor costs. Historically, fork-lift pallets have been constructed of wood, having a plurality of parallel stringers on which are nailed or otherwise secured one or more structural members defining a pallet platform. The pallet platform can be composed of multiple wood strips or unitary wood panels, such as plywood panels, to provide a generally planar support surface on which the goods or articles are appropriately arranged or stacked. The parallel stringers raise the product support platform above a floor surface and thereby permit the forks of a fork-lift truck to be inserted within spaces defined between the stringers. This enables a fork-lift truck to lift and move the pallet with all of its articles as a unit or package. Typically, the pallet will remain with the products or articles until such time as the articles are removed from the pallet for further handling, for use or for distribution.
Even though pallets are typically of low cost, they are sufficiently costly that they are used many times for shipment of products before they become sufficiently worn or damaged that replacement is necessary. Although wood has historically been a low cost commodity, thus enabling pallets to be manufactured of wood at low cost, of late, the cost of wood for products such as pallets has significantly increased, thus causing pallet manufacturers to seek other sources for materials. Pallets have been constructed of extruded or formed metal such as steel or aluminum.
With the growth of the plastics industry a wide variety of plastics have been investigated to determine their suitability for use in producing pallets. Plastic pallets can easily be molded and are stronger and lighter weight than wooden pallets. They can also be made with recyclable materials. Furthermore, plastic pallets are more durable than wooden pallets, however, may be subject to weakness as the amount of material is reduced to lower weight and cost.
To increase the durability of plastic pallets, various reinforcing elements or rods have been used. While the reinforcing elements have improved the strength of the pallets, many applications, referred to as clean applications, prohibit exposed reinforcing elements. Encasing the reinforcing elements within the pallet plastic has proven challenging as the difference in thermal coefficient between the plastic and the metal of the reinforcing elements has resulted in cracking or other adverse effects. Attempts to avoid the thermal effects have resulted in complex systems, for example, preformed, full length sleeves to separately encase the reinforcing elements. Such sleeves have added to the cost and complexity of manufacturing the pallets.